A Predictive Model of Hearing Outcome for Cochlear Implantation in Children below 5 Years of Age

ABSTRACT

Background: Cochlear Implantation (CI) has become an important modality of treatment for children with severe to profoundpre-lingual sensorineural hearing loss who do not benefit from hearing aids (HAs). The final outcome is not totally predictable,as there are a large number of factors which either alone or in combination will play their roles in the final outcome of CI.Aim of the Study This study aims to evaluate prospectively the relative impact of multiple pre-, peri-, and post-operative factorson the final outcome of the CI in pre-lingual hearing impaired children aged 5 years under “Sruthitharangam” free cochlearimplant program of Government of Kerala.Materials and Methods: This study was conducted at Government Medical College, Kozhikode (GMC-KKD), Kerala, fromJanuary 2014 to January 2015. The study group consisted of 60 patients screened from the patients who have attendedAuditory verbal habilitation (AVH) categories of Auditory Performance (CAP) test, Meaningful auditory integration scale (MAIS)and Speech intelligibility rating test (SIR) at GMC-KKD, Kerala. Counseling of parents was done regarding regular follow-upsand therapy/support to the child at home.Observations and Results: Pearson correlation test and Spearman correlation test were done to check the correlation betweenage at which HA was first fitted and MAIS scores. Correlation between the age at which HA first fitted and MAIS was negative.As the age at which HAs were fitted increases, the MAIS score decreases. This indicates the significance of using the residualhearing and stimulation of auditory nerve as early as possible. Pearson correlation and Spearman correlation tests were appliedto check the correlation between age of surgery and MAIS score and found that there was negative correlation existing betweenage of surgery and MAIS scores. This meant, as the age at which surgery was done increases, the MAIS score decreases.Pearson correlation test and Spearman correlation tests were applied to check the MAIS scores and duration of AVH with HAs.Conclusions: A Cochlear implant was not a passive sensory aid or sensory substitution device that simply replaces a damaged ordefective cochlea to restore normal hearing but requires prolonged period of aural rehabilitation that involves perceptual learning,adaptation, and readjustment of their attention. The various risk factors that affect the auditory gain and speech perception eitheracting singly or in combination and the statistical analysis of the present study showed are the age at implantation, duration ofauditory deprivation, and the residual hearing which have a direct impact on the outcome over a period of 1 year.